Fuel injection nozzle for externally ignited internal combustion engines

ABSTRACT

In a fuel injection nozzle there is disposed a valve member which, during normal operation, maintains the nozzle open but which, when actuated by a control liquid admitted to the nozzle in a control conduit, hermetically obturates the nozzle opening.

United States Patent Eckert s] 3,656,693 [451 Apr. 18,1972

[54] FUEL INJECTION NOZZLE FOR EXTERNALLY IGNITED INTERNAL COMBUSTION ENGINES [72] Inventor: Konrad Eckert, Stuttgart-Bad Cannstatt,

Gennany [73] Assignee: Robert Bosch Gmbll, Stuttgart, Germany [22] Filed: July 9, 1970 [21] Appl. No.: 53,587

[30] Foreign Application Priority Data July 9, 1969 Germany ..P 19 34 704 .7

[52] U.S. Cl ..239/4l0, 239/412, 239/424,

239/426, 239/584 [51] Int. Cl ..B05b 7/12 [58] Field oiSearch ..239/407,408,4l0,412,418,

[56] References Cited UNITED STATES PATENTS 3,083,913 4/1963 Coffman et al. ..239/583 X Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-Edwin D. Grant Attorney-Edwin E. Greigg ABSTRACT In a fuel injection nozzle there is disposed a valve member which, during normal operation, maintains the nozzle open but which,'when actuated by a control liquid admitted to the nozzle in a control conduit, hermetically obturates the nozzle opening.

5 Claims, 4 Drawing Figures BACKGROUND OF THE mvi-zrmon This invention relates to a fuel injection nozzle for externally ignited internal combustion engines of automotive vehicles. The said noule is of the type wherein the fuel is injected into a suction tube of the engine, first, by means of a liquid nozzle through an intermediate air chamber and thereafter, by means of an intermediate nozzle which; is aligned with the liquid nozzle. The intermediate air chamber is supplied with air under pressure.

The purpose of fuel injection nozzles of the aforenoted type is to premix the fuel with pressurized air prior to its injection into the suction tube in order to achieve a better combustion. Known fuel injection nozzles of this type (such as disclosed in German Pat. No. 1,085,377, and US. Pat. No. 3,330,541) are,

for a favorable metering of fuel, usually disposed in the vicinity of the suctionvalves of the engine. Using such nozzles it may. not be avoided that during coasting in gear (that is, when the engine is rotated by the rolling vehicle and the butterfly valve is closed) fuel is drawn by means of the strong vacuum through the injection nozzle into the liquid nozzle'and then into the engine cylinder. In most cases the fuel-air mixture thus obtained is not combustible; consequently, the proportion of poisonous ingredients of the exhaust gases increases. Or, if said mixture is combustible, jerky operation of the engine results.

OBJECT AND SUMMARY OF THE INVENTION It is an object of the invention to provide an improved fuel injection nozzle in which the aforenoted disadvantages, particularly during coasting in gear, are eliminated. Briefly stated, according to the invention, in the fuel injection nozzle there is disposed a valve or closing member which maintains the liquid noule open during normal operation, and

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic view of a fuel injection system incorporating the fuel, injection nozzle according to the invention;

FIG. 2 is an axial sectional view of a preferred embodiment of a fuel injection nozzle according to the invention;

FIG. 3 is a sectional view along line III-III of FIG. 2; and FIG. 4 is a sectional view along line IV-IV of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now to FIG. I, in the fuel injection system shown,

the intake air drawn in the direction of the arrow through the suction tube 1 flows past an arbitrarily operable butterfly valve 2'and an impact plate 3 arranged nonnal to the direction of flow. Therefrom the air flows to the cylinders (not shown) of an internal combustion engine (also not shown).

The fuel is drawn from a tank 4 by means of a fuel pump 6 driven by an electromotor 5 and is continuously delivered through a fuel conduit 7 to a fuel metering device 8. From the conduit 7 there extends a return conduit 9 which terminates in the fuel tank 4 and in which there is disposed a pressure limiting valve 10 for the purpose of maintaining the pressure constant in the fuel conduit. From the fuel metering device 8 there extend fuel conduits 11 (only one shown) each of which leads to an injection nozzle 12.

A three-dimensional cam is rotatable by the impact plate 3 through a guide rod 13 and a lever 14. The three-dimensional cam 15 is further axially displaced by means not shown,

'. with an appropriate bore cross section when the butterfly valve 2 performs a rotary motion. With the three-dimensional cam 15 there is associated a follower pin 16 of the fuel metering device 8. In this manner, dependent upon the'position of the arbitrarily operable butterfly valve 2 and the pressure responsive impact plate 3, the fuel is metered by the fuel metering device 8.

In addition to the fuel pump 6, the electromotor 5 also drives an air pump 18 which delivers air under a predetermined pressure through conduit 19 to each injection nozzle From the fuel conduit 7 there leads a control conduit 21 to the injection nozzle 12. In the control conduit 21 there is contained a shut-ofl' member 22 which may be opened, for example, by means of a pneumatic setting member 23. The latter is connected, through a conduit24, with a locationof suction tube 1 that is' downstream of the impact plate 3. In this manner, during coasting in gear, when the butterfly valve 2 and the impact plate 3 are both in a closedposition, the vacuum generated in the suctiontube causes opening of the shut-ofi member 22. As a result, communication is established between the pressurized fuel conduit 7 and the control conduit 21. The pressure thus transmitted to the latter affects the fuel injection nozzle 12 as will be set forth hereinbelow.

In order to ensure that the control pressure in the control conduit 21 is higher than the injection pressure in the conduit 11,'there is provided a pressure reducing valve 25 in the conduit 7.

Turning now to FIGS. 2, 3 and 4, in the fuel injection nozzle shown, the fuel is admitted from the conduit ll'through a channeled coupling ring '27 and radial bore 28 to an annular chamber 30 provided in a sleeve 29 threadedly held in a nozzle holder 33. The inner boundary of the annular chamber 30 is defined by a tube 31, the inner bore of which is connected with the control conduit 21 through a bore 32 extending axially in the sleeve 29. The sleeve 29 axially delirnits an annular chamber 34 communicating with the conduit 19 through a radial bore 35. The inner boundary of the annular chamber 34 is formed by a casing 36, the frontal face of which'contains a central opening which constitutes a liquid nozzle 37. The casing 36 is, together with a replaceable nonle ring 38, clamped between the sleeve 29 and the nozzle holder 33. V

The casing 36-includes a coaxial inner tube portion 36'. In this manner a jacketed structure is obtained. In the inner bore 36" there is held the end portion of the tube 31. The annular chamber 39 defined by the walls 36 and 36 communicates with the annular chamber 30 through a filter 40.

'From the annular chamber 39 the fuel admitted through conduit 11 is introduced through tangentially merging bores 41 into a vortex chamber 42 (FIG. 3) and therefrom it is injected in a turbulent condition, through the liquid nozzle 37 into an intermediate air chamber 43 which is defined by the nozzle ring 38. From the intermediate air chamber or premixing chamber 43 the fuel-air mixture is injected through the intermediate or secondary nozzle 44 into the suction tube of the internal combustion engine. As shown in FIG. 4, in the nozzle ring 38 there are provided radial bores 45, the cross section of which has a predetermined value. Thus, dependent upon the pressure of the air, i.e., the desired air flow, a nozzle ring 38 may. be selected and built into the nozzle.

' In the inner bore 36" there is reciprocable and rotatable with a snug fit a piston 47, a radial face 48 of which is affected by the control liquid admitted through the conduit 21. In case the control liquid is sufiiciently pressurized, the piston 47 moves downwardly and displaces with its other radial face 49 a valve member 50 against the force of a return spring 51 and against the pressure prevailing in the vortex chamber 42. At the end of such movement, the terminus of the valve member 50 hermetically obturates the liquid nozzle 37. The valve member 50 is guided by a stationary ring 52 provided with axially extending grooves 52' which establish communication between the vortex chamber 42 and the chamber accommodating the spring 51.

movable into and out of a closed When .the control conduit 21 is depressurized (for example,

by interrupting hydraulic communication between conduits 7 and 21), the return spring 51 causes the valve stem 50 to be withdrawn and, as a result, theliquid nozzle 37 is reopened.

By virtue of the bores 45 merging radially into the inter- That which is claimed is:

1. In a fuel injection noule associated with an externally ignited, internal combustion engineincluding a suction tube,

said fuelinjection nozzle being of the known type that includes (A) a liquid nozzle, (8) anintennediate air chamber into whichfuel is introduced through said liquid nozzle, (C)

means for introducing air under pressure into said inter-- mediate air chamber and (D) an intermediate or secondary nozzle injecting fuel from said intermediate air chamber into said suction tube, the improvement comprising, i

A. a closing means cooperating with said liquid nozzle and 2 position in which said liquid nozzle'is obturated thereby,

B. liquid control means to move said closing means,

C. return means'in engagement with said closing means and opposing the force exerted thereon by liquid control 25 means, i D. a .vortex chamber provided insaid fuel injection noule upstream of and in communication with said liquid nozzle and E. at least one fuel channel merging tangentially in said vortex chamber. 2. In a fuel injection nozzle associated with an externally ignited-intemal combustion engine including a suction tube, said fuel injection nozzle being of the known type that includes (A) a liquid nozzle, (B) an intermediate airchamber into which fuel is introduced through said liquid nozzle, (C) means for introducing air under pressure into said intermediate air chamber and (D) an intermediate or secondary nozzle injecting fuel from said intermediate air chamber into said suction tube, the improvement comprising,

40 A'. liquid control means, B. closing means cooperating with said liquid nozzle. and including l'. a valve member movable into and out of contact with said liquid nozzle for respectively closing and opening the latter, I

2. a reciprocable-piston having a. a first radial face exposed to said liquid control .means, b. a section radial face operatively connected to said valve'member to displace the latter when said piston shifts in response to said liquid control means and C. return means in engagement with said closing means and 4 opp means.

' 3. An improvement as defined in claim 2, wherein said second radial face of said piston is exposed to the pressure of fuel upstream of said liquidnozzle, said last-named pressure forming part of said return means. a

i 4. in a fuel injection nozzle associated with an externally ignited internal combustion engine including a suction tube, said fuel injection noule being of the known type that in cludes (A) a liquid nozzle, (B) an intermediate air chamber into which fuel is introduced through said liquid nonle, (C) meansfor introducing air under pressure into said intermediate airchamber and (D) an intemiediate orsecondary noule injectingfuel from'said intermediate air chamber into said suction tube, the improvement comprising,

A. a closing means cooperating with said liquid nozzle and movable into and out of a closedposition in which said liquid noule is obturated thereby,

B. liquid control means to move said closing return means in engagement with said c opposing the forces exerted thereon by said liquid control D. an 'exchangeable'nozzle ring forming part-of said means for introducing air under pressure into said intermediate air charnber,-said ring includingat least one air channel of predetermined cross section carrying air intosaid intermediate air chamber. I I

5. In a fuel injection nozzle associated with an internal combustion engine including a suction tube, the improvement comprising A. housing means, y

B. a liquid nozzle disposed within said housing means,

C. first channel means in said housing for introducing fuel to said noule,

D. an intermediate air chamber disposed within said housing and adjoining said liquid nozzle downstream thereof, E. second channel'means in said housing for introducing air under pressure into said intermediate air chamber,

F. an intermediate nonle disposed in said housing and adjoining said intermediate air chamber downstream thereof, said intermediate nozzle being in continuous communication with said intermediate air chamber, with said second channel means and with saidsuction tube,

G. closing means cooperating solely with said liquid nozzle, said closing means being movable into a closed position to obturate said liquid nozzle and into an open position to establish communication between said intermediate air chamber and said first channel means,

H. liquid control means for moving said closingmeans and l. retum means in engagement with said closing means and opposing the force exerted thereon by said liquid control means.

means,

force exerted thereon by said liquid control 7 oslng means and 

1. In a fuel injection nozzle associated with an externally ignited internal combustion engine including a suction tube, said fuel injection nozzle being of the known type that includes (A) a liquid nozzle, (B) an intermediate air chamber into which fuel is introduced through said liquid nozzle, (C) means for introducing air under pressure into said intermediate air chamber and (D) an intermediate or secondary nozzle injecting fuel from said intermediate air chamber into said suction tube, the improvement comprising, A. a closing means cooperating with said liquid nozzle and movable into and out of a closed position in which said liquid nozzle is obturated thereby, B. liquid control means to move said closing means, C. return means in engagement with said closing means and opposing the force exerted thereon by said liquid control means, D. a vortex chamber provided in said fuel injection nozzle upstream of and in communication with said liquid nozzle and E. at least one fuel channel merging tangentially in said vortex chamber.
 2. In a fuel injection nozzle associated with an externally ignited internal combustion engine including a suction tube, said fuel injection nozzle being of the known type that includes (A) a liquid nozzle, (B) an intermediate air chamber into which fuel is introduced through said liquid nozzle, (C) means for introducing air under pressure into said intermediate air chamber and (D) an intermediate or secondary nozzle injecting fuel from said intermediate air chamber into said suction tube, the improvement comprising, A. liquid control means, B. closing means cooperating with said liquid nozzle and including
 2. a reciprocable piston having a. a first radial face exposed to said liquid control means, b. a section radial face operatively connected to said valve member to displace the latter when said piston shifts in response to said liquid control means and C. return means in engagement with said closing means and opposing the force exerted thereon by said liquid control means.
 3. An improvement as defined in claim 2, wherein said second radial face of said piston is exposed to the pressure of fuel upstream of said liquid nozzle, said last-named pressure forming part of said return means.
 4. In a fuel injection nozzle associated with an externally ignited internal combustion engine including a suction tube, saiD fuel injection nozzle being of the known type that includes (A) a liquid nozzle, (B) an intermediate air chamber into which fuel is introduced through said liquid nozzle, (C) means for introducing air under pressure into said intermediate air chamber and (D) an intermediate or secondary nozzle injecting fuel from said intermediate air chamber into said suction tube, the improvement comprising, A. a closing means cooperating with said liquid nozzle and movable into and out of a closed position in which said liquid nozzle is obturated thereby, B. liquid control means to move said closing means, C. return means in engagement with said closing means and opposing the forces exerted thereon by said liquid control means and D. an exchangeable nozzle ring forming part of said means for introducing air under pressure into said intermediate air chamber, said ring including at least one air channel of predetermined cross section carrying air into said intermediate air chamber.
 5. In a fuel injection nozzle associated with an internal combustion engine including a suction tube, the improvement comprising A. housing means, B. a liquid nozzle disposed within said housing means, C. first channel means in said housing for introducing fuel to said nozzle, D. an intermediate air chamber disposed within said housing and adjoining said liquid nozzle downstream thereof, E. second channel means in said housing for introducing air under pressure into said intermediate air chamber, F. an intermediate nozzle disposed in said housing and adjoining said intermediate air chamber downstream thereof, said intermediate nozzle being in continuous communication with said intermediate air chamber, with said second channel means and with said suction tube, G. closing means cooperating solely with said liquid nozzle, said closing means being movable into a closed position to obturate said liquid nozzle and into an open position to establish communication between said intermediate air chamber and said first channel means, H. liquid control means for moving said closing means and I. return means in engagement with said closing means and opposing the force exerted thereon by said liquid control means. 